On this page
NEET biology asks you to classify plants by structure: root systems, stems, leaves and life cycles. The idea of grouping plants by their visible form and then explaining it has an author. His name was Theophrastus, and he is often called the father of botany. This post covers who he was, how he classified plants, a passage on the Indian banyan that Indian students will recognise, and the method you can borrow for your own revision.
Who was Theophrastus?
The Stanford Encyclopedia of Philosophy entry on Theophrastus gives the details, drawing on the ancient biographer Diogenes Laertius. He was born around 371 BCE in Eresos on the island of Lesbos, and his original name was Tyrtamus. He studied in Plato's Academy, where he met Aristotle, and later travelled with him. When Aristotle left Athens in 323 BCE, Theophrastus succeeded him as head of the school at the Lyceum and led it for some 35 years. He is reported to have lectured to as many as two thousand pupils at a time. He died around 287 BCE and left his books, including Aristotle's manuscripts, to a student.
The Stanford entry on Aristotle's biology sums up the partnership: Aristotle investigated animals systematically, and Theophrastus did the same for plants. Our post on Aristotle's study of animals tells the other half.
What did he write about plants?
Two botanical works survive: Enquiry into Plants, in nine books, and Plant Explanations, in six. The Stanford entry calls them the first systematisation of the botanical world. In the Enquiry he examined over 550 species, looking at their structure, growth and reproduction, wild and cultivated plants, timber, and in Book 9 the medicinal uses of plant juices, gums and resins. The Enquiry gathers the facts; Plant Explanations tries to find their causes.
How did Theophrastus classify plants?
In Book I of the Enquiry, in Arthur Hort's 1916 Loeb translation, he names the first and most important classes as tree, shrub, under-shrub and herb, and defines each by form:
Tree: grows from the root with a single stem, having knots and several branches, and cannot easily be uprooted. Examples: olive, fig, vine.
Shrub: rises from the root with many branches. Example: bramble.
Under-shrub: rises from the root with many stems as well as many branches. Example: rue.
Herb: comes up from the root with its leaves and has no main stem, with the seed borne on the stem. Examples: corn and pot-herbs.
Then comes the sentence that makes him a scientist rather than a list-maker. These definitions, he says, "must be taken and accepted as applying generally and on the whole." He gives the example of mallow, which under cultivation can grow tall and tree-like within six or seven months.
What did he say about the banyan tree?
In the same book, discussing roots, Theophrastus singles out the "Indian fig", which Hort identifies as the banyan. He writes that this plant "sends out roots from the shoots till it has a hold on the ground and roots again", so that a ring of roots forms around the tree at a distance from the main stem. More than two thousand years later, the NCERT Class 11 Biology chapter on morphology of flowering plants still uses the banyan as its example of adventitious roots, which arise from parts of the plant other than the radicle. You can revise the chapter in our guide to morphology of flowering plants.
How is this different from modern plant classification?
His classes are based on habit, the overall growth form, which is still how field guides and NCERT describe plants as herbs, shrubs and trees. Modern taxonomy, starting with Carl Linnaeus and later evolutionary classification, groups plants by reproductive structures and ancestry instead. A banyan and a wheat plant end up far apart in both systems, but a vine, which Theophrastus called a tree, would be placed by its flowers and fruit today.
What mistakes do students make on plant classification questions?
Treating habit as taxonomy. "Shrub" describes growth form, not a taxonomic group. Do not use it to answer a question about families or divisions.
Mixing up root systems. A tap root grows from the radicle, as in mustard; fibrous roots come from the base of the stem, as in wheat; adventitious roots arise elsewhere, as in the banyan. Check where the root starts.
Ignoring exceptions. Many NEET questions test the borderline case. Learn the rule and one exception together.
What can a student take from Theophrastus?
He collected widely, grouped by stated features, admitted where his groups broke down and then went looking for causes. That is a good revision routine for any classification chapter. When you want to see how one concept connects to the next, the Fermi Concept Library covers every concept in biology, each with its own lesson and its place in the map.
Try it: list ten plants from your neighbourhood, sort them into Theophrastus's four classes, and write down which ones did not fit cleanly and why.
